package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {
    @Resource
    private IUserService userService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IFollowService followService;

    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog -> {
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    /**
     * 点赞
     * @param id
     * @return
     */
    @Override
    public Result likeBlog(Long id) {
        //1. 获取登录用户
        Long userId = UserHolder.getUser().getId();
        //2. 判断当前登录用户是否已经点赞
        String key =  RedisConstants.BLOG_LIKED_KEY + id;
//        Boolean isMember = stringRedisTemplate.opsForSet().isMember(key, userId.toString());
        // 2. 改进  使用SortedSet  zscore 判断当前用户是否已经点赞
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        //3. 如果未点赞，可以点赞
//        if (BooleanUtil.isFalse(isMember)) {
        if (score == null) {
            //3.1 数据库点赞数+1
            boolean isSuccess = update().setSql("liked = liked + 1").update();
            //3.2 保存用户到Redis的set集合
            //改进 3.2 保存用户到redis的SortedSet集合
            if(isSuccess){
//                stringRedisTemplate.opsForSet().add(key,userId.toString());
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }else{
            //4. 如果已点赞，取消点赞
            //4.1 把数据库点赞数 -1
            boolean isSuccess = update().setSql("liked = liked - 1").update();
            //4.2 把用户从Redis的set集合移除
            if(isSuccess){
//                stringRedisTemplate.opsForSet().remove(key,userId.toString());
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }

    /**
     * 点赞排行榜
     * @param id
     * @return
     */
    @Override
    public Result queryBlogLikes(Long id) {
        //1. 查询top5的点赞用户 zrange key 0 4
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(RedisConstants.BLOG_LIKED_KEY+id, 0, 4);
        if(top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        //2. 解析出其中的用户id
        List<Long> userId = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String ids = StrUtil.join(",", userId);
        List<UserDTO> userDTOList = userService
//                .listByIds(userId)          //3. 根据用户id查询用户  存在顺序问题
                .query().in("id",userId)
                .last("order by field(id,"+ids+")").list()
                .stream().map(user ->{
                    if(StrUtil.isBlank(user.getIcon())){
                        user.setIcon("/imgs/icons/default-icon.png");
                    }
                    return BeanUtil.copyProperties(user, UserDTO.class);
                })
                .collect(Collectors.toList());
//        System.out.println("查看点赞成员："+userDTOList);
        //4. 返回
        return Result.ok(userDTOList);
    }

    /**
     * 保存用户笔记信息
     * @param blog
     * @return
     */
    @Override
    public Result saveBlog(Blog blog) {
        //1. 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        //2. 保存探店笔记
        boolean isSuccess = save(blog);
        if(!isSuccess){
            return Result.fail("新增笔记失败");
        }
        //3. 查询笔记作者的所有粉丝
        List<Follow> fanList = followService.query().eq("follow_user_id", user.getId()).list();
        //4. 推送笔记id给所有粉丝
        for (Follow follow : fanList){
            String key = RedisConstants.FEED_KEY+follow.getUserId();
            stringRedisTemplate.opsForZSet().add(key, blog.getId().toString(), System.currentTimeMillis());
        }
        //5. 返回id
        return Result.ok(blog.getId());
    }

    /**
     * 滚动分页查询
     * @param max  上一次查询的最小时间戳
     * @param offset  上一次查询相同的最小时间戳的个数
     * @return
     */
    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //1. 获取当前用户
        Long userId = UserHolder.getUser().getId();
        String key = RedisConstants.FEED_KEY+userId;
        //2. 查询收件箱
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        //3. 非空判断
        if(typedTuples == null || typedTuples.isEmpty()){
            return Result.ok();
        }
        //4. 解析数据：blogId、minTime(时间戳)、offset
        List<Long> blogId = new ArrayList<>(typedTuples.size());
        Long minTime = 0l;
        int count = 1;
        for(ZSetOperations.TypedTuple<String> typedTuple:typedTuples){
            blogId.add(Long.valueOf(typedTuple.getValue()));
            max = typedTuple.getScore().longValue();
            if(minTime == max){
                count++;
            }else{
                minTime = max;
                count = 1;
            }
        }
        //5. 根据id查询blog
        String idStr = StrUtil.join(",", blogId);
        List<Blog> blogs = query().in("id", blogId)
                .last("order by field(id,"+idStr+")").list();
        for (Blog blog : blogs) {
            //5.2. 查询blog有关的用户
            queryBlogUser(blog);
            //5.3. 查询blog是否被点赞
            isBlogLiked(blog);
        }
        //6. 封装并返回
        ScrollResult scrollResult = new ScrollResult();
        scrollResult.setList(blogs);
        scrollResult.setMinTime(minTime);
        scrollResult.setOffset(count);

        return Result.ok(scrollResult);
    }


    /**
     * 根据id查询blog
     * @param id
     * @return
     */
    @Override
    public Result queryBlogById(Long id) {
        //1、 查询blog
        Blog blog = getById(id);
        if(blog == null){
            return Result.fail("笔记不存在");
        }
        //2. 查询blog有关的用户
        queryBlogUser(blog);
        //3. 查询blog是否被点赞
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    /**
     * 查询blog是否被点赞
     * @param blog
     */
    private void isBlogLiked(Blog blog) {
        //1. 获取登录用户
        UserDTO user = UserHolder.getUser();
        if(user == null){
            //用户未登录，不需要查询点赞数
            return ;
        }
        Long userId = user.getId();
        //2. 判断当前登录用户是否已经点赞
        String key = "blog:liked:" + blog.getId();
//        Boolean isMember = stringRedisTemplate.opsForSet().isMember(key, userId.toString());
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }

    /**
     * 查询blog作者
     * @param blog
     */
    private  void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }
}
